Check your emergency kits, the New Zealand Red Cross has urged, as much of the country prepares to be lashed by severe weather today and tomorrow.

The North Island is braced for a sub-tropical storm bringing heavy rain, gales, and potential coastal flooding to most of the North Island.

Strong onshore winds mean that king tides today and Friday, coupled with waves the size of a double-decker bus, pose a threat to many low-lying communities.

All northward facing bays in Auckland, coastlines from Northland to the Bay of Plenty and Firth of Thames, and the North Island's west coast from tomorrow, are at risk.


The storm is on track to hit the top of the North Island this morning, sweeping across the island before hitting northern and eastern regions of the South Island on Friday and clearing the country on Saturday.

Niwa warned the approaching storm bore similarities to ex-Tropical Cyclone Ita, which struck at Easter three years ago. It inundated coastal communities across the upper North Island and blew buildings to pieces on the South Island's West Coast.

The storm was expected to peak early Friday, head analyst Philip Duncan said.

The worst of the winds could become hurricane force - 120 km/h - for a time at the centre, although such winds would stay mainly out at sea, Duncan said.

MetService forecast up to 160mm of rain would fall over Mt Taranaki and the Nelson and Bay of Plenty ranges.

Coromandel was expecting 150mm and Northland 120mm, while Auckland was in line for up to 90mm, with torrential downpours this evening.

Campers in coastal areas and flood plains have been told to move to higher ground, with waves up to 7m high expected to hammer North Island coastlines on Friday.

Residents in flood-prone areas such as the Hauraki Plains have also been told to gather supplies and be ready to evacuate.

Waikato Regional Council regional hazards team leader Rick Liefting said the rain would coincide with a king tide tonight, hindering the ability of fast-flowing coastal rivers to run out.

"Combined with dry catchments there is the real potential for localised flooding and coastal inundation," he said.

Hauraki District Council Civil Defence Controller Steve Fabish said people should have supplies ready in case they are cut off.

"They should also put some prior thought into where they might self-evacuate to, such as friends and family."

New Zealand Red Cross disaster response manager Andrew McKie said people should have a "getaway bag" with food, water, a radio, torch, wet-weather clothes, sturdy footwear and personal items.

Pills, medical equipment, pet food and a lead should be ready to go. Digitise photos and important documents or store them up high in plastic, and don't leave dangerous chemicals on the ground, McKie said.

Know how to get to high ground with good escape routes, fill the car with petrol and plan where to meet family in an emergency, he said.


• Have at least a three day supply of water handy.
• Store plenty canned or dried food.
• Check batteries for flashlights every three months.
• Have a first aid kit handy.
• Have some extra cash ready.
• Download the 'Hazards' Red Cross app